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food source · 1
Almonds are among the richest foods in vitamin E: a handful (about 28 g) has about 7 mg, close to half of an adult's daily need. Vitamin E sits in cell membranes and shields unsaturated fats from free radicals.
Mechanism · It guards the fats in membranes
Vitamin E dissolves in fat and sits in cell membranes, where it takes the hit from free radicals for the unsaturated fats that oxidize easily. Almonds are full of oil and carry plenty of vitamin E at the same time, which makes evolutionary sense: it protects the almond's own fat. Taking the molecule on its own in a high-dose capsule is a different matter.
Numbers · A handful of almonds
Almonds have about 25.6 mg of alpha-tocopherol per 100 g against an adult need of about 15 mg a day, so a handful of about 28 g gives about 7 mg, close to half a day's need. The calories come with the fat: a handful is a source, a jar is a lot of energy. Only about 20% of the calcium in almonds is absorbed, because phytate and tough cell walls both hold it back, so almonds are no substitute for milk.
synergy · 3
Glutathione peroxidase, a selenium-containing enzyme, breaks down hydrogen peroxide in the watery part of the cell, and vitamin E stops the chain oxidation of fats in the cell membrane. They intercept reactive oxygen in different places, and when one is short, the other has to carry more of the load.
Vitamin C works as an antioxidant in the watery fluid inside and outside cells, and vitamin E guards the fats of the cell membrane. After E stops a free radical it is oxidized itself, and C can restore it so it keeps working; this step comes mainly from laboratory studies.
Highly unsaturated fatty acids such as EPA and DHA oxidize more easily, so cell membranes need more vitamin E to protect them. The more omega-3 you take in, the more vitamin E you need; fish-oil supplements themselves may already be oxidized in the bottle.
antagonism · 1
High-dose vitamin E supplements may interfere with activating the vitamin K–dependent clotting factors and raise bleeding risk; people on anticoagulants such as warfarin, or recovering from surgery, need particular care. Vitamin E from food does not cause this problem.
regulates · 1
After vitamin E stops a free radical in a cell membrane, it becomes a tocopheroxyl radical itself and needs vitamin C to restore it. Large trials of vitamin E supplements found no cardiovascular benefit; one explanation from test-tube work is that high-dose vitamin E on its own lets these radicals build up, but that has not been measured directly in people.